The present invention relates to a variable valve damper for the inlet valves of reciprocating, internal combustion engines so that they will be able to change the amount of fluid compressed while operating; thereby effectively changing the size and power output of the engine.
At the present time most two stroke and four stroke internal combustion engines compress the same ammount of fluid at all operating conditions. They do not change the amount of fluid compressed to vary the power of the engine. To vary the power of the engine, they vary the fuel to fluid ratio and this varies the temperature. As the temperature varies from the design temperature, the efficiency of the engine decreases. In addition, present engines compress and expand their charge in the same volume. This results in under expansion of the charge when the power piston reaches the end of its power stroke, and the release of pressurized fluid that still has the ability to do work. If the engine expanded the charge more, it would be more efficient.
Previous inventions that delayed the closing of the engines inlet valve by using a damper had the valve stem as part of the damper, and the cylinder as part of the cylinder head. Engines of this type are the subject of patent application: Warren, Aug. 16, 2000, application Ser. No. 09/638,950. The present invention is a modification of an internal combustion, reciprocating, engine by attaching a variable damper to the engine. The cylinder of the variable damper is attached to the cylinder head and the piston is attached to the valve. The engine requires minimum modification.
This invention is: the addition of: xe2x80x9cAn inlet valve damperxe2x80x9d to the inlet valve of an internal combustion engine so that it can reduce the amount of fluid sucked into the engine by allowing some of the fluid to be pushed back out before the compression cycle. This is accomplished by delaying the inlet valve""s closing.
When the variable inlet valve damper causes the inlet valve to remain open so that some fluid is pushed back out, the amount of fluid to be compressed is reduced and the engine operates in a reduced power mode with the possibility of almost complete expansion of the fluid-fuel charge. When the variable inlet valve damper does not damp, and allows the inlet valve to close as soon as fluid starts to leave the engine, the engine operates in a greater power output mode.
The advantage of the variable inlet valve damper is: The engine can be operated at full power where it has the same efficiency as an engine without a variable inlet valve damper, or it can be operated at reduced power where, because of increased expansion, it has more efficiency than at full power. Transferring this, for example, to an airplane for take off, the engine with a variable inlet valve damper has about the same power and efficiency an engine without a variable inlet valve damper. For cruise conditions, the engine without a variable inlet valve damper loses efficiency because it operates at lower temperature. An engine with a variable inlet valve damper increases in efficiency because it operates near the same temperature and has greater expansion. Therefore, this engine will get more miles per gallon. In addition, since this is an improvement to an existing engine it will not require massive expense and development.